Assuntos
Anafilaxia/etiologia , Hipersensibilidade Alimentar/epidemiologia , Estações do Ano , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Boston/epidemiologia , Criança , Pré-Escolar , Feminino , Hipersensibilidade Alimentar/complicações , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Luz Solar , Raios Ultravioleta , Vitamina D/sangue , Adulto JovemRESUMO
TFIID is a multiprotein complex consisting of the TATA box binding protein and multiple tightly associated proteins (TAFIIs) that are required for transcription by selected activators. We previously reported cloning and partial characterization of human TAFII130 (hTAFII130). The central domain of hTAFII130 contains four glutamine-rich regions, designated Q1 to Q4, that are involved in interactions with the transcriptional activator Sp1. Mutational analysis has revealed specific regions within the glutamine-rich (Q1 to Q4) central region of hTAFII130 that are required for interaction with distinct activation domains. We tested amino- and carboxyl-terminal deletions of hTAFII130 for interaction with Sp1 activation domains A and B (Sp1A and Sp1B) and the N-terminal activation domain of CREB (CREB-N) by using the yeast two-hybrid system. Our results indicate that Sp1B interacts almost exclusively with the Q1 region of hTAFII130. In contrast, Sp1A makes multiple contacts with Q1 to Q4 of hTAFII130, while CREB-N interacts primarily with the Q1-Q2 hTAFII130 subdomain. Consistent with these interaction studies, overexpression of the Q1-to-Q4 region in HeLa cells inhibits Sp1- but not VP16-mediated transcriptional activation. These findings indicate that the Q1-to-Q4 region of hTAFII130 is required for Sp1-mediated transcriptional enhancement in mammalian cells and that different activation domains target distinct subdomains of hTAFII130.
Assuntos
Proteínas de Ligação a DNA/metabolismo , Glutamina/metabolismo , Fator de Transcrição Sp1/metabolismo , Fatores Associados à Proteína de Ligação a TATA , Fator de Transcrição TFIID , Fatores de Transcrição/metabolismo , Sítios de Ligação , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Regulação da Expressão Gênica , Genes Reporter , Células HeLa , Humanos , Mutação , Ligação Proteica , Fator de Transcrição Sp1/genéticaRESUMO
Transcription factor TFIID is a multiprotein complex composed of the TATA box-binding protein (TBP) and multiple TBP-associated factors (TAFs). TFIID plays an essential role in mediating transcriptional activation by gene-specific activators. Numerous transcriptional activators have been characterized from mammalian cells; however, molecular analysis of the components of mammalian TFIID has been incomplete. Here we describe isolation of cDNAs encoding two TAF subunits of the human transcription factor TFIID. The first cDNA is predicted to encode the C-terminal 947 residues of the 130-kDa human TAF subunit, hTAFII130. The second cDNA encodes the C-terminal 801 residues of the 100-kDa subunit, hTAFII100. Recombinant TAFs expressed in human cells by transient transfections are capable of associating with the endogenous TAFs and TBP to form a TFIID complex in vivo. Protein binding experiments demonstrate that hTAFII130, like its Drosophila homolog dTAFII110, interacts with the glutamine-rich activation domains of the human transcription factor Sp1. Furthermore, hTAFII130 shows reduced binding to the Sp1 mutants with impaired ability to activate transcription, suggesting a role for hTAFII130 as a direct coactivator target for Sp1.
